docs: Improve docs for `Point` and `Vec2` #552

Job	Run time
cargo clippy (windows-latest)	1m 19s
cargo clippy (wasm32)	43s
cargo check (msrv) (windows-latest)	1m 5s
cargo clippy (macos-latest)	38s
cargo check (msrv) (wasm32)	19s
cargo check (msrv) (macos-latest)	30s
cargo clippy (ubuntu-latest)	41s
cargo doc	21s
cargo check (msrv) (ubuntu-latest)	25s
cargo fmt	20s
cargo test (windows-latest)	1m 2s
cargo test (wasm32)	20s
cargo test (macos-latest)	22s
typos	6s
cargo test (ubuntu-latest)	17s
	8m 28s

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